Semiconductor device and method of manufacturing the same

Abstract

A ferroelectric capacitor formed above a semiconductor substrate includes a lower electrode, a dielectric film (ferroelectric film) having ferroelectric characteristics, and an upper electrode. The upper electrode includes a conductive oxide film made of a ferroelectric material to which conductivity is provided by adding a conductive material such as Ir, and the conductive oxide film is in contact with the dielectric film.

What is claimed is: 
     
       1. A method of manufacturing a semiconductor device, the method comprising:
 forming a lower electrode film above a semiconductor substrate; 
 forming a dielectric film made of a ferroelectric material on the lower electrode film by a sputtering method; 
 subjecting the dielectric film to a crystallization treatment; and 
 forming a conductive oxide film on the dielectric film, the conductive oxide film being made of a ferroelectric material to which conductivity is provided by adding a conductive material, 
 wherein the ferroelectric material forming the conductive oxide film is PZT, the conductive material is at least one of iridium and ruthenium, and a percentage content of the conductive material in the ferroelectric material forming the conductive oxide film is not less than 1 mol % and not more than 4 mol %, and 
 the forming the lower electrode film includes:
 forming a noble metal film made of a noble metal above the semiconductor substrate; and 
 forming an amorphous noble metal oxide film, made of an oxide of a noble metal that is the same as the noble metal forming the noble metal film, on the noble metal film, a film thickness of the noble metal oxide film being equal to or more than 0.1 nm and equal to or less than 3 nm. 
 
 
     
     
       2. The method of manufacturing a semiconductor device according to  claim 1 , wherein the ferroelectric material forming the dielectric film is the same as the ferroelectric material forming the conductive oxide film. 
     
     
       3. The method of manufacturing a semiconductor device according to  claim 1 , wherein a film thickness of the conductive oxide film is not less than 0.1 nm and not more than 50 nm. 
     
     
       4. The method of manufacturing a semiconductor device according to  claim 1 , further comprising:
 forming a first conductive film made of a conductive oxide on the conductive oxide film; and 
 forming a second conductive film made of a conductive oxide on the first conductive film. 
 
     
     
       5. The method of manufacturing a semiconductor device according to  claim 4 , further comprising: crystallizing the conductive oxide film between the forming the first conductive film and the forming the second conductive film. 
     
     
       6. The method of manufacturing a semiconductor device according to  claim 4 , wherein a degree of oxidation of the conductive oxide forming the first conductive film is lower than a degree of oxidation of the conductive oxide forming the second conductive film. 
     
     
       7. The method of manufacturing a semiconductor device according to  claim 4 , wherein the first conductive film is an iridium oxide film. 
     
     
       8. The method of manufacturing a semiconductor device according to  claim 1 , wherein
 the conductive oxide film is formed by
 forming an amorphous dielectric film on the dielectric film, 
 forming an oxide film containing the conductive material on the amorphous dielectric film, and 
 diffusing the conductive material from the oxide film to the amorphous dielectric film. 
 
 
     
     
       9. The method of manufacturing a semiconductor device according to  claim 8 , wherein a temperature during the formation of the oxide film containing the conductive material is 200° C. or above. 
     
     
       10. The method of manufacturing a semiconductor device according to  claim 4 , further comprising: forming a conductive noble metal film by sputtering a noble metal onto the second conductive film in an Ar atmosphere. 
     
     
       11. The method of manufacturing a semiconductor device according to  claim 1 , wherein the noble metal film is a platinum film, and the noble metal oxide film is a platinum oxide film. 
     
     
       12. The method of manufacturing a semiconductor device according to  claim 1 , wherein the conductive oxide film is formed by a sputtering method at a film formation temperature that is equal to or higher than room temperature and equal to or lower than 50° C.